This invention relates generally to aerial ropeways and the supporting of sheave trains used therewith and more specifically to the ensurement that the haul cables of the aerial ropeways remain in the sheave trains.
A problem that exists in aerial ropeways is the chance of deropement wherein the haul cable or rope will separate from the sheave train. There are many reasons for deropement such as a vibration in the rope due to the power plant, the wind, an uneven load and others. There have been many attempts to prevent such deropements. Some of the devices have been successful but are very expensive or difficult to apply to existing installations. Others have not proven to be successful. This problem is particularly troublesome when the haul cables or ropes have to span a great distance which generally results in high rope lines, large changes in the haul cable or rope""s slope, and large increases in the size of the haul cable or rope in addition to the above-mentioned problems. Therefore, there continues to exist a need for an efficient apparatus for preventing such deropement.
This invention provides an articulated crossarm for an aerial ropeway so that the haul cable or rope will remain in the sheave train of the aerial ropeway. In a preferred embodiment of the invention, the aerial ropeway comprises an articulated crossarm which is supported by suitable apparatus at a desired location. The articulated crossarm has first sheave train supporting apparatus and first pivot apparatus for pivotally connecting the first sheave train supporting apparatus and the articulated crossarm and second sheave train supporting apparatus and second pivot apparatus for pivotally connecting the second sheave train supporting apparatus and the articulated crossarm. The first and second pivot apparatus are spaced apart a desired distance. A rigid elongated member or tie bar is provided and has opposite end portions. A third pivot apparatus pivotally connects one of the opposite end portions and the first sheave train supporting apparatus and a fourth pivot apparatus pivotally connects the other of the opposite end portions and the second sheave train supporting apparatus. In a preferred embodiment of the invention, the apparatus for supporting the articulated crossarm comprises first and second support towers fixedly mounted at spaced apart locations. At least two support cables spaced apart a predetermined distance are mounted on and extend between the first and second support towers. The ends of the support cables are securely fastened in fixed foundations. The articulated crossarm has opposite end sections each of which is secured to one of the at least two support cables.
The first and second sheave train supporting apparatus preferably comprise a first reaction arm mounted on the first pivot apparatus for pivotal movement. A first sheave train supporting apparatus is mounted on the first reaction arm and has a portion extending outwardly therefrom and a first sheave train is mounted on this outwardly extending portion. A second reaction arm is mounted on the second pivot apparatus for pivotal movement. A second sheave train supporting apparatus is mounted on the second reaction arm and has a portion extending outwardly therefrom. A second sheave train is mounted on this outwardly extending portion.
A continuous haul cable extends between at least two spaced apart rotatable pulleys and drive apparatus is provided for rotating at least one of the two spaced apart rotatable pulleys to move the continuous haul cable so that spaced apart portions of the continuous haul cable are located in the first and second sheave trains at all times. A plurality of carrying vehicles or gondolas are secured to the haul cable at spaced apart intervals for movement therewith and pass over the first and second sheave trains.
When the aerial ropeway is in a static or equilibrium position, the first, second, third and fourth pivot apparatus are located so that, when a line between the first and second pivot apparatus lies in a horizontal plane and another line between the third and fourth pivot apparatus is parallel to and spaced from the line, the first sheave train is directly below the first pivot apparatus and the second sheave train is directly below said second pivot apparatus. The lines between the first, second, third and fourth pivot apparatus preferably form a trapezoid wherein the distance between the first and second pivot apparatus is greater than the distance between the third and fourth pivot apparatus and the distance between the first and third pivot apparatus is substantially the same as the distance between the second and fourth pivot apparatus.
In some instances, the articulated crossarm of this invention is supported directly on the support cables. However, in other instances, the articulated crossarm is located a distance below the support cables so that super structure is added to the articulated crossarm and this superstructure is supported on the support cables. The articulated crossarm may also be mounted on the conventional towers of a conventional ski lift.
The following are explanations of the operation of the articulated crossarm of this invention when there is an uneven load, in that the carrying vehicles or gondolas secured to the haul cable on one side of the haul cable have a much heavier load than the carrying vehicles on the other side of the haul cable, and when the carrying vehicles or gondolas and the haul cable are subjected to a cross wind. In the event of an uneven load, the line between the first and second pivot apparatus would not lie in a horizontal plane so that the haul cable on the heavier side of the line would be below the horizontal plane and the haul cable on the lighter side of the line would be above the horizontal plane. If the crossarm was not articulated, the first and second sheave trains would be at an angle to the haul cable. However, with the articulated crossarm, the reaction arms and the tie bar have cooperated to position the first and second sheave trains so that the portions of the haul cable, having or not having a carrying vehicle or gondola located thereon, are located correctly in the first and second sheave trains. In the event of a cross wind, with or without an uneven load condition, a force tending to move the haul cable out of the correct position in the first and second sheave trains would be created. However, with the articulated crossarm, the reaction arms and the tie bar have cooperated to position the first and second sheave trains so that the portions of the haul cable, having or not having a carrying vehicle or gondola located thereon, are located correctly in the first and second sheave trains so that no force exists that would tend to move the haul cable out of the first and second sheave trains, exists.